Intravenous thrombolysis in ischemic stroke with unknown onset using CT perfusion.

BACKGROUND: Acute ischemic stroke patients with unclear onset time presenting >4.5 h from last-seen-normal (LSN) time are considered late patients and excluded from i.v. thrombolysis. We aimed to evaluate whether this subgroup of patients is different from patients presenting >4.5 h from a witnessed onset, in terms of eligibility and response to computed tomography perfusion (CTP)-guided i.v. thrombolysis. METHODS: We prospectively studied consecutive acute non-lacunar middle cerebral artery (MCA) ischemic stroke patients presenting >4.5 h from LSN. All patients underwent multimodal CT and were considered eligible for i.v. thrombolysis according to CTP criteria. Two patient groups were established based on the knowledge of the stroke onset time. We compared the proportion of candidates suitable for intravenous thrombolysis between both groups, and their outcome after thrombolytic therapy. RESULTS: Among 147 MCA ischemic stroke patients presenting >4.5 h from LSN, stroke onset was witnessed in 74 and unknown in 73. Thirty-seven (50%) patients in the first group and 32 (44%) in the second met CTP criteria for thrombolysis (P = 0.7). Baseline variables were comparable between both groups with the exception of age, which was higher in the unclear onset group. The rates of early neurological improvement (54.1% vs 46.9%), 2-h MCA recanalization (43.5% vs 37%), symptomatic hemorrhagic transformation (3% vs 0%) and good 3-month functional outcome (62.2% vs 56.3%) did not differ significantly between both groups. CONCLUSION: Delayed stroke patients with unknown onset time were no different than patients >4.5 h regarding eligibility and response to CTP-based i.v. thrombolysis.

Collateral circulation on perfusion-computed tomography-source images predicts the response to stroke intravenous thrombolysis.

BACKGROUND AND PURPOSE: Perfusion-computed tomography-source images (PCT-SI) may allow a dynamic assessment of leptomeningeal collateral arteries (LMC) filling and emptying in middle cerebral artery (MCA) ischaemic stroke. We described a regional LMC scale on PCT-SI and hypothesized that a higher collateral score would predict a better response to intravenous (iv) thrombolysis. METHODS: We studied consecutive ischaemic stroke patients with an acute MCA occlusion documented by transcranial Doppler/transcranial color-coded duplex, treated with iv thrombolysis who underwent PCT prior to treatment. Readers evaluated PCT-SI in a blinded fashion to assess LMC within the hypoperfused MCA territory. LMC scored as follows: 0, absence of vessels; 1, collateral supply filling ≤ 50%; 2, between> 50% and < 100%; 3, equal or more prominent when compared with the unaffected hemisphere. The scale was divided into good (scores 2-3) vs. poor (scores 0-1) collaterals. The predetermined primary end-point was a good 3-month functional outcome, while early neurological recovery, transcranial duplex-assessed 24-h MCA recanalization, 24-h hypodensity volume and hemorrhagic transformation were considered secondary end-points. RESULTS: Fifty-four patients were included (55.5% women, median NIHSS 10), and 4-13-23-14 patients had LMC score (LMCs) of 0-1-2-3, respectively. The probability of a good long-term outcome augmented gradually with increasing LMCs: (0) 0%; (1) 15.4%; (2) 65.2%; (3) 64.3%, P = 0.004. Good-LMCs was independently associated with a good outcome [OR 21.02 (95% CI 2.23-197.75), P = 0.008]. Patients with good LMCs had better early neurological recovery (P = 0.001), smaller hypodensity volumes (P < 0.001) and a clear trend towards a higher recanalization rate. CONCLUSIONS: A higher degree of LMC assessed by PCT-SI predicts good response to iv thrombolysis in MCA ischaemic stroke patients.

[Perfusion computed tomography makes it possible to overcome important SITS-MOST exclusion criteria for the endovenous thrombolysis of cerebral infarction]. / La tomografia computarizada de perfusion permite superar importantes criterios de exclusion SITS-MOST para la trombolisis endovenosa del infarto cerebral.

AIM. To study the frequency, safety and efficacy of perfusion computed tomography (PCT), through identification of brain tissue-at-risk, to guide intravenous thrombolysis in stroke patients with regulatory exclusion criteria (SITS-MOST and ECASS-3). PATIENTS AND METHODS. We studied consecutive acute non-lacunar ischemic stroke patients. After conventional CT was considered eligible, PCT was performed in the following circumstances: 4.5 to 6 h window, wake-up stroke or unknown time of onset; extent early infarct signs on CT; minor or severe stroke; seizures or loss of consciousness. Intravenous 0.9 mg/kg alteplase was indicated if: cerebral blood volume lesion covered < 1/3 of middle cerebral artery territory; mismatch > 20% between mean transit time and cerebral blood volume maps existed; and informed consent. SITS-MOST safety-efficacy parameters were used as endpoint variables. RESULTS. Between May 2009-April 2010, 66 hyperacute ischemic stroke patients a priori not eligible for intravenous thrombolysis underwent PCT. Indications were: > 4.5 h in 18 patients, wake up stroke or unknown onset in 25, extent infarct signs in 6, seizures at onset in 11, and minor stroke (NIHSS < 4) in 6. Twenty-nine (44%) of them finally received intravenous thrombolysis. Symptomatic hemorrhagic transformation occurred in 2 (6.9%) patient and 18 (62.1%) achieved a modified Rankin scale score equal or less than 2 on day 90. CONCLUSION. A high proportion of acute stroke patients with SITS-MOST and ECASS-3 exclusion criteria can be safely and efficaciously treated with intravenous thrombolysis using a PCT selection protocol. However randomized control trials will be needed to confirm our results.

[Nummular headache: clinical features and therapeutic experience in a series of 30 new cases]. / Cefalea numular: caracteristicas clinicas y experiencia terapeutica en una serie de 30 nuevos casos.

INTRODUCTION: Nummular headache (NH) is a mild or moderate pain, located in a small, well circumscribed, rounded or elliptical area. Temporal pattern is variable and pain exacerbations have been described. AIM. To analyze clinical characteristics and therapy requirement and response in a series of patients attended due to NH in a headache outpatient office. PATIENTS AND METHODS: 30 patients (18 females, 12 males) diagnosed as NH. We considered demographic and nosological characteristics, temporal pattern, presence and intensity of exacerbations, and requirement of symptomatic or preventive therapies. RESULTS: Age at onset 49.2 ± 18.1 years (range: 21-79 years). Two of the patients presented a bifocal NH and we analyzed 32 areas, 28 rounded and 4 elliptical. Diameter: 4.7 ± 1.1 cm. Regarding locations occipital (10 areas, 31.3%), parietal (9 areas, 28.1%) and frontal (6 areas, 18.8%). Pain intensity of 5.2 ± 1.8 on a ten-point visual analogical scale. Regarding temporal profile, in 18 areas (56.3%) was chronic, in 5 (15.6%) episodic and undefined due to a scarce time from onset in 9 (28.1%). In 16 areas (50%) pain exacerbations lasting from 3 seconds to 15 minutes occurred. Nine (30%) patients did not improve with symptomatic drugs, and at least one preventative was prescribed in 23 (76.6%) patients without consistent effectiveness. CONCLUSIONS: NH is not an uncommon diagnosis in an outpatient headache office. In our series, basal pain intensity is moderate and symptomatic drugs commonly provide no relief. So, patients frequently need a preventive therapy.

Incidence and influence on referral of primary stabbing headache in an outpatient headache clinic.

Primary stabbing headache (PSH) is a pain, as brief, sharp, jabbing stabs, predominantly felt in the first division of trigeminal nerve. Population studies have shown that PSH is a common headache. However, most people suffer attacks of low frequency or intensity and seldom seek for medical assistance. There are few clinic-based studies of PSH, and its real influence as a primary cause for referral to neurology outpatient offices is to be determined. We aim to investigate the burden of PSH as main complaint in an outpatient headache clinic. We reviewed all patients with PSH (ICHD-II criteria), attended in an outpatient headache clinic in a tertiary hospital during a 2.5-year period (January 2008-June 2010). We considered demographic and nosological characteristics and if PSH was main cause of submission. 36 patients (26 females, 10 males) out of 725 (5%) were diagnosed of PSH. Mean age at onset 34.1 ± 2.9 years (range 10-72). Mean time from onset to diagnosis 68.8 ± 18.3 months. Twenty-four patients fulfilled ICHD-II criteria for other headaches (14 migraine, 6 tension-type headache, 2 hemicrania continua, 1 primary cough headache and 1 primary exertional headache). 77.7% of patients were submitted from primary care. In 14 patients (39%), PSH was main reason for submission, its intensity or frequency in 5 (35.7%) and fear of malignancy in 9 (74.3%). Only two patients of those who associated other headaches were submitted due to PSH. In conclusion, PSH is not an uncommon diagnosis in an outpatient headache office. However, and according to our data, it is not usually the main cause of submission to a headache clinic.

Constraints on the duration and freshwater release of Heinrich event 4 through isotope modelling.

Heinrich events--abrupt climate cooling events due to ice-sheet instability that occurred during the last glacial period--are recorded in sediment cores throughout the North Atlantic Ocean. Modelling studies have described likely physical mechanisms for these events, but the quantitative characteristics of Heinrich events are less well known. Here we use a climate model of intermediate complexity that explicitly calculates the distribution of oxygen isotopes in the oceans to simulate Heinrich event 4 at about 40,000 yr ago. We compare an ensemble of scenarios for this Heinrich event with oxygen isotope data measured in foraminiferal calcite of a comprehensive set of sediment cores. From this comparison, we obtain a duration of 250 +/- 150 yr and an ice release of 2 +/- 1 m sea-level equivalent for Heinrich event 4, significantly reducing the uncertainties in both values compared to earlier estimates of up to 2,000 yr and 15 m of sea-level equivalent ice release, respectively. Our results indicate that the consequences of Heinrich events may have been less severe than previously assumed, at least with respect to Greenland climate and sea level.

Simulating the amplification of orbital forcing by ocean feedbacks in the last glaciation.

According to Milankovitch theory, the lower summer insolation at high latitudes about 115,000 years ago allowed winter snow to persist throughout summer, leading to ice-sheet build-up and glaciation. But attempts to simulate the last glaciation using global atmospheric models have failed to produce this outcome when forced by insolation changes only. These results point towards the importance of feedback effects-for example, through changes in vegetation or the ocean circulation-for the amplification of solar forcing. Here we present a fully coupled ocean-atmosphere model of the last glaciation that produces a build-up of perennial snow cover at known locations of ice sheets during this period. We show that ocean feedbacks lead to a cooling of the high northern latitudes, along with an increase in atmospheric moisture transport from the Equator to the poles. These changes agree with available geological data and, together, they lead to an increased delivery of snow to high northern latitudes. The mechanism we present explains the onset of glaciation-which would be amplified by changes in vegetation-in response to weak orbital forcing.